1. Field of the Invention
The present invention relates to a signal processing device for a solid-state imaging device, an imaging apparatus having the signal processing device, a signal processing method, and a program.
2. Description of the Related Art
A solid-state imaging device such as a CCD image sensor or CMOS image sensor has a structure in which a color filter and a light-collecting micro-lens are formed in the order listed on a surface of a pixel including a photoelectric conversion element. In such a solid-state imaging device, since a color filter is interposed between a pixel and a micro-lens, the distance between the pixel and the micro-lens is increased by the filter. When a distance between pixels is reduced in proportion to a reduction of pixel size, the possibility of inter-pixel color mixing increases because a light ray which has passed through a certain pixel can more easily enter another pixel in the neighborhood.
As a solution to such a problem, JP-A-2004-135206 (Patent Document 1) discloses a color mixing reducing device which subtracts a certain percentage of signal components from a signal for a pixel of interest in a particular color, the percentage being calculated from signals for surrounding pixels (in colors other than the particular color) adjacent to the pixel of interest. In order to calculate a certain percentage of signal components as thus described, the color mixing reducing device uses a uniform correction parameter for each of row and column directions of a pixel array surface on which a plurality of pixels are two-dimensionally arranged.
However, it is known that mixing of the color of a pixel of interest with the colors of a plurality of surrounding pixels adjacent to the same does not necessarily occur in an isotropic manner in an actual solid-state imaging device. As a solution to this, JP-A-2007-142697 (Patent Document 2) discloses a signal processing apparatus which corrects a signal for a pixel of interest using each of signals for a plurality of surrounding pixels adjacent to the pixel of interest and a correction parameter independently set for each of the signals. In order to cope with the anisotropy of color mixing, this signal processing apparatus uses a correction parameter which is uniform in a pixel array surface and which is set for each signal (color).